Not sure if he's my favorite, but one of my favorites is Steve Albini...not only because he's produced some great albums from great artists (Nirvana, The Jesus Lizard, Pixies, Helmet, Don Caballero, and many more), but because of his old-school, minimalist recording philosophy. Many other producers spend so much time getting "the perfect sound" for each instrument, and then take days to get "the perfect take" for each song. Not Steve Albini. He just sticks the band in a room with some mics. If the band sounds good in the room, then the recording will sound good.

Name dropping a couple of big ones here; Tom Dowd and Phil Spector. Page for sure.

On a relevant side note I'm really diggin' Ski Beatz as well. He's a hip hop producer, that recently did an album. A lot of the samples he used on it weren't able to be cleared in time or at all by the record labels. So he took the samples, did some really off keel things with them (the kind of audio processing that doesn't get done too often in hip hop anymore), and then had a band (the Senseis) learn and play the samples on the album. By the way this is the direction hip hop is going in. It's actually costing more to clear samples than hire live musicians.

I'm aware of only a few, George Martin (if you don't know him, you just arrived on the planet, where's your papers?) Chas Chandler is another. Here's one I took notice of right from get-go back in the day, Eddy Offord. http://nfte.org/interviews/EO234.html